What do you do if your system fails to boot properly? This appendix discusses some common failures and ways to alleviate them.

Power-on Initialization Sequence

Familiarize yourself with the system power-on initialization messages. You can then identify problems more accurately because these messages show you the types of functions the system performs at various stages of system start-up. They also show the transfer of control from POST to the OpenBoot firmware to the Booter to the kernel.

The example that follows shows the OpenBoot initialization sequence in a SPARCstation 10 system. The messages before the banner appear on TTYA only if the
diag-switch?
parameter is true.

Note - The displayed kernel messages may vary depending on the version of the operating system you are using

describes commands that are useful in some failure situations. When issuing any of these commands, hold down the keys immediately after turning on the power to your system, until the keyboard LEDs flash.

TABLE D-1 Emergency Keyboard Commands

Command

Description

Stop

Bypass POST. This command does not depend on security-mode. (Note: some systems bypass POST as a default; in such cases, use
Stop-D
to start POST.)

Stop-A

Abort.

Stop-D

Enter diagnostic mode (set
diag-switch?
to
true
).

Stop-F

Enter FORTH on TTYA instead of probing. Use
fexit
to continue with the initialization sequence. Useful if hardware is broken.

Stop-N

Reset NVRAM contents to default values.

Note - These commands are disabled if the PROM security is on. Also, if your system has full security enabled, you cannot apply any of the suggested commands unless you have the password to get to the ok prompt.

Preserving Data After a System Crash

The
sync
command forces any information on its way to the hard disk to be written out immediately. This is useful if the operating system has crashed, or has been interrupted without preserving all data first.

sync
actually returns control to the operating system, which then performs the data saving operations. After the disk data has been synchronized, the operating system begins to save a core image of itself. If you do not need this core dump, you can interrupt the operation with the
Stop-A
key sequence.

Common Failures

This section describes some common failures and how you can fix them.

Blank Screen - No Output

Problem: Your system screen is blank and does not show any output.

Here are possible causes for this problem:

Hardware has failed.

Refer to your system documentation.

Keyboard is not attached.

If the keyboard is not plugged in, the output goes to TTYA instead. To fix this problem, power the system down, plug the keyboard in, and power on again.

Monitor is not turned on or plugged in.

Check the power cable on the monitor. Make sure the monitor cable is plugged into the system frame buffer; then turn the monitor on.

output-device
is set to TTYA or TTYB.

This means the NVRAM parameter
output-device
is set to
ttya
or
ttyb
instead of being set to
screen
. You can do one of the following:

Power the system down. Then turn it on, and immediately press
Stop-N
. This sets all NVRAM parameters to their default values. As a result, the
output-device
parameter is set to
screen
. Be warned that all previous non-default settings are reset to their default values as well. You must restore them as needed.

Connect a terminal to TTYA and reset the system. After getting to the
ok
prompt on the terminal, type:
screen output
to send output to the frame buffer. Use
setenv
to change the default display device, if needed.

System has multiple frame buffers.

If your system has several plugged-in frame buffers, or it has one built-in frame buffer and one or more plugged in, then it is possible that the wrong frame buffer is being used as the console device. See
Setting the Console to a Specific Monitor
.

System Boots From the Wrong Device

Problem: Your system is supposed to boot from the disk; instead, it boots from the net.

There are two possible causes for this:

The
diag-switch?
NVRAM parameter is inadvertently set to
true
.

Interrupt the booting process with
Stop-A
. Type the following commands at the
ok
prompt:

ok setenv diag-switch? false

ok boot

The system should now start booting from the disk.

The
boot-device
NVRAM parameter is set to
net
instead of
disk
.

Interrupt the booting process with
Stop-A
. Type the following commands at the
ok
prompt:

ok setenv boot-device disk

ok boot

Note that the preceding commands cause the system to boot from the disk defined as
disk
(target 3) in the device aliases list. If you want to boot from
disk1
(target 1),
disk2
(target 2), or
disk3
(target 3), set
boot-device
accordingly.

Problem: Your system is booting from a disk instead of from the net.

boot-device
is not set to
net
.

Interrupt the booting process with
Stop-A
. Type the following commands at the
ok
prompt:

ok setenv boot-device net

ok boot

Problem: Your system is booting from the wrong disk. (For example, you have more than one disk in your system. You want the system to boot from disk2, but the system is booting from disk1 instead.)

boot-device
is not set to the correct disk.

Interrupt the booting process with
Stop-A
. Type the following commands at the
ok
prompt:

ok setenv boot-device disk2

ok boot

System Will Not Boot From Ethernet

Problem: Your system fails to boot from the net.

The problem could be one of the following:

NIS maps are out of date.

Report the problem to your system administrator.

Ethernet cable is not plugged in.

Plug in the ethernet cable. The system should continue with the booting process.

Server is not responding:
no carrier
messages.

Report the problem to your system administrator.

tpe-link-test
is disabled.

Refer to the troubleshooting information in your system documentation. (Note: systems that do not have Twisted Pair Ethernet will not have the
tpe-link-test
parameter.)

System Will Not Boot From Disk

Problem: You are booting from a disk and the system fails with the message:
The file just loaded does not appear to be executable.

The boot block is missing or corrupted.

Install a new boot block.

Problem: You are booting from a disk and the system fails with the message:
Can't open boot device
.

The disk may be powered down (especially if it is an external disk).

Turn on power to the disk, and make sure the SCSI cable is connected to the disk and the system.

SCSI Problems

Problem: Your system has more than one disk installed, and you get
SCSI-related errors.

Your system might have duplicate SCSI target number settings.

Try the following procedure:

1. Unplug all but one of the disks.

2. At the
ok
prompt, type:

ok probe-scsi-all

Note the target number and its corresponding unit number.

3. Plug in another disk and perform step b again.

4. If you get an error, change the target number of this disk to be one of the unused target numbers.

5. Repeat steps b, c, and d until all the disks are plugged back in.

Setting the Console to a Specific Monitor

Problem: You have more than one monitor attached to the system, and the console is not set to an intended monitor.

If you have more than one monitor attached to the system, the OpenBoot firmware always assigns the console to the frame buffer specified by the
output-device
NVRAM parameter. The default value of
output-device
is
screen
, which is an alias for the first frame buffer that the firmware finds in the system.

A common way to change this default is to change
output-device
to the appropriate frame buffer:

ok nvalias myscreen /obio/cgfourteen

ok setenv output-device myscreen

ok reset

Another way of setting the console to a specific monitor is to change the
sbus-probe-list
NVRAM parameter.

ok show sbus-probe-list (Display the current and default values)

sbus-probe-list f0123 f0123 (Your system may have a different number of SBus slots)

ok

If the frame buffer that you are choosing as the console is in slot 2, change
sbus-probe-list
to probe slot 2 first: